This invention relates to a adjusting mechanism, more particularly, to an adjusting mechanism for a seat post with an offset.
The seat post of a bicycle is used to support the seat of a bicycle through fastening the seat rails thereof. Furthermore, an adjustment of the seat can also be made by the help of the seat post. As shown in FIG. 1, the typical seat post 10a of a bicycle includes a clamp mechanism 20a which is fixed to a tube 12a. The clamp mechanism 20a includes a lower clamp member 21a and a upper clamp 22a wherein the upper clamp member 22a and the lower clamp member 21a can be fastened to the clamp base 23a through two bolt members 24a, 25a. By this arrangement, the seat rail of the seat can be fixed thereto. On the other hand, the lower and upper clamp 21a, 22a can jointly make an angular adjustment with respect to the clamp base 23a.
On the other hand, there is another typical seat post wherein the center line of the clamp base has an offset to the axis of the tube member, see FIG. 2. The offset of the clamp base can provide a longer distance between the seat post and the stem member of the handlebars. This design can provide at least the following advantages. 1) A larger room can be gained for the legs of a rider. 2) For the off-road riding, more tracking force can be gained since the center of the weight of a rider is closer to the rear wheel.
Although the conventional seat post, as shown in FIG. 2, with an offset has the above described advantages, they typically do not provide a secure clamping or a fine angular adjustment as with a twin bolts fixed upper clamp arrangement, see FIG. 1. This kind of seat post, as shown in FIG. 2, only has one bolt 24b to attach the upper clamp 22b to the lower clamp 21b. The lower and upper clamp 21b, 22b can not make an angular adjustment with respect to the clamp base 23b.
On the other hand, in some cases, the clamp member of the conventional seat post is inclined with the tube member. Accordingly, the adjustment of the front bolt is very difficult since the axis of the front bolt intersects with the axis of the tube member. Accordingly, the room for adjusting is very small.